Carmody
23rd December 2010, 17:46
http://news.sciencemag.org/sciencenow/2010/08/tapping-tesla-to-save-trapped-mi.html
In early January 2006, a methane explosion tore through a coal mine in Sago, West Virginia, trapping 13 miners nearly 100 meters underground. Cut off from communicating with the miners, authorities could not determine where they were—or even if they were still alive. By the time rescuers reached the miners 2 days later, all but one had died.
After the incident, Gary Smith, a retired engineer, sent a letter to his ex-manager at the Lockheed Martin Corp. in Syracuse, New York. Smith, who grew up in a West Virginia mining family, asked his former colleagues if anyone knew of a technology that could provide reliable communications during such disasters. After reading reports of the Sago incident and discussing similar emergencies with federal mine safety officials, the Lockheed Martin engineers updated a very old one.
The team focused on a concept developed over a century ago by Nikola Tesla. The noted pioneer in electricity and radio had shown that a magnetic wave generator could be used for wireless communications.
Basically, the generator works like an electromagnet. Powered by standard alternating current or battery, it runs electricity through a wire that is coiled around a metal cylinder, creating a harmless, low-energy magnetic field that extends for hundreds of meters. Just like radio, the field can carry an audio signal by modulating (raising or lowering) its strength instant by instant. But unlike radio, cell phones, and satellite phones—whose electromagnetic waves can't pass very far through rock, clay, or other materials that conduct electricity—a magnetically generated signal penetrates the ground easily. On the other end, a coiled antenna wire about 100 meters long receives the signal, and an amplifier converts it into sound.
In the 1890s, Tesla experimented with the concept as a possible alternative to Marconi's wireless telegraph. But the device's relatively short range and high signal noise made it impractical for widespread use. Short range is not a problem in most mine situations, explains engineer David LeVan, who led the Lockheed Martin research team. The devices the group developed, called the MagneLink Magnetic Communication System, combine a refrigerator-size magnetic generator with a briefcase-size receiving antenna. One such unit operates on the surface; the other, down in the mine. LeVan says tests earlier this year at a mine in Mavisdale, Virginia, showed that the low-frequency signal can penetrate through 500 meters of solid rock, making it usable in more than 85% of underground mines in the United States.
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What this means, is..that the unit has a terrible Signal To Noise ratio. Well, where does this poor S/N ration come from? Interference, obviously. This means it can also be used to do radar work. The point, is that the poor S/N is actually useful signal, when looked at in the right way.
The other point..is that you have here, an approximate 500-700 Meter distance capable EM pulsing communication system that works through rock.
In early January 2006, a methane explosion tore through a coal mine in Sago, West Virginia, trapping 13 miners nearly 100 meters underground. Cut off from communicating with the miners, authorities could not determine where they were—or even if they were still alive. By the time rescuers reached the miners 2 days later, all but one had died.
After the incident, Gary Smith, a retired engineer, sent a letter to his ex-manager at the Lockheed Martin Corp. in Syracuse, New York. Smith, who grew up in a West Virginia mining family, asked his former colleagues if anyone knew of a technology that could provide reliable communications during such disasters. After reading reports of the Sago incident and discussing similar emergencies with federal mine safety officials, the Lockheed Martin engineers updated a very old one.
The team focused on a concept developed over a century ago by Nikola Tesla. The noted pioneer in electricity and radio had shown that a magnetic wave generator could be used for wireless communications.
Basically, the generator works like an electromagnet. Powered by standard alternating current or battery, it runs electricity through a wire that is coiled around a metal cylinder, creating a harmless, low-energy magnetic field that extends for hundreds of meters. Just like radio, the field can carry an audio signal by modulating (raising or lowering) its strength instant by instant. But unlike radio, cell phones, and satellite phones—whose electromagnetic waves can't pass very far through rock, clay, or other materials that conduct electricity—a magnetically generated signal penetrates the ground easily. On the other end, a coiled antenna wire about 100 meters long receives the signal, and an amplifier converts it into sound.
In the 1890s, Tesla experimented with the concept as a possible alternative to Marconi's wireless telegraph. But the device's relatively short range and high signal noise made it impractical for widespread use. Short range is not a problem in most mine situations, explains engineer David LeVan, who led the Lockheed Martin research team. The devices the group developed, called the MagneLink Magnetic Communication System, combine a refrigerator-size magnetic generator with a briefcase-size receiving antenna. One such unit operates on the surface; the other, down in the mine. LeVan says tests earlier this year at a mine in Mavisdale, Virginia, showed that the low-frequency signal can penetrate through 500 meters of solid rock, making it usable in more than 85% of underground mines in the United States.
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
What this means, is..that the unit has a terrible Signal To Noise ratio. Well, where does this poor S/N ration come from? Interference, obviously. This means it can also be used to do radar work. The point, is that the poor S/N is actually useful signal, when looked at in the right way.
The other point..is that you have here, an approximate 500-700 Meter distance capable EM pulsing communication system that works through rock.